Elasticity and Related Properties

The bearing of elasticity on structure has been frequently referred to by Scarth (70) and myself (81). In Scarth s words, elasticity is the chief quality of protoplasm on which a conjecture of the ultramicroscopic structure of living matter can be based. But our interest in elasticity need not 

An important observation by Pease (66) answers a long controversy on the place where the elasticity of a cell is situated it is not concentrated at the surface as has been frequently maintained. This observation by Pease (66) is in agreement with a contention I have long held (81), namely, that the elastic properties of protoplasm are distributed throughout the substance and do not reside merely at the surface. This fact in no way detracts from the reality and significance of surface elasticity (43). 

All students of this general problem should become familiar with the work done on the structural features of rubber, notably by Mooney (67), Treloar (96), Guth (31), Meyer (63), and Mark (48). 

Plowe and the writer (89) determined the effects of salts on protoplasm and found that calcium increases extensibility while sodium diminishes it, and magnesium has no effect at all. The following lyotropic ionic series was obtained Ca Sr Mg K Li Na. 

The foregoing state of affairs appears to hold for living muscle. As myosin muscle is and must be extensible, but, as a living machine, it is contractile only. We are forced, therefore, to question the work of Hill (35) and others in which it was shown that muscle in the relaxed state resembles rubber, that the stretch-strain curves of the two are similar, that the stretching forces are of the same order of magnitude, and that both rubber and muscle exhibit the same anomalous thermoelastic behavior (at 

---

Treloar LRG. The elasticity and related properties of rubbers. Rep Prog Phys 1973 36 755-826. 

This document gives definitions of terms related to the non-ultimate mechanical behaviour or mechanical behaviour prior to failure of polymeric materials, in particular of bulk polymers and concentrated solutions and their elastic and viscoelastic properties. 

A. -B. Chen, A. Sher and W. T. Yost, Elastic Constants and Related Properties of Semiconductor Compounds and Their Alloys D. R. Clarke, Fracture of Silicon and Other Semiconductors H. Siethoff, The Plasticity of Elemental and Compound Semiconductors S. Guruswamy, K. T. Faber and J. P. Hirth, Mechanical Behavior of Compound Semiconductors... 

Polyurethanes have a combination of elastic and viscous properties that can be explained in standard engineering terms using DMA methods. Information can be obtained on the properties of polyurethanes that relates to the storage and dissipation of energy applied during use. 

Joern Petersson, Julio Gonzalo, and Jinzo Kobayashi, Dielectric, Elastic and Thermal Properties, Computer Simulations and NMR of Ferroelectrics and Related Materials, Gordon 8c Breach, Amsterdam, The Netherlands, 1998. 

A.-B. Chen, A. Sher, and W. T. Yost, Elastic Constants and Related Properties of Semiconductor Compounds and Their Alloys... 

Accuracy The potential function must be able to accurately reproduce quantities such as energies, bond lengths, elastic constants, and related properties that enter a fitting database. 

The biomechanical response of the body has three components, (1) inertial resistance by acceleration of body masses, (2) elastic resistance by compression of stiff structures and tissues, and (3) viscous resistance by rate-dependent properties of tissue. For low-impact speeds, the elastic stiffness protects from crush injuries whereas, for high rates of body deformation, the inertial and viscous properties determine the force developed and limit deformation. The risk of skeletal and internal organ injury relates to energy stored or absorbed by the elastic and viscous properties. The reaction load is related to these responses and inertial resistance of body masses, which combine to resist deformation and prevent injury. When tissues are deformed beyond their recoverable limit, injuries occur. 

What are the elastic and inelastic properties ( y, X j, X, e, e, G,J, where i and = 1, 2, 3, within this interphase region, and how do they vary with radial distance from the fiber Also, are they isotropic and uniform along the length of the fiber How are the interphase properties related to the microstructure (Materials/Mechanics/Chemistry)... 

Another method for measuring mechanical properties on the macroscopic scale uses the relation between mechanical properties and the propagation of acoustic waves [89]. The velocity of sound waves and also the damping thereof can be directly deduced from the elastic and viscous properties. For polymers, ultrasound can be used since the damping of the acoustic waves is decreased at high frequencies. However, this method seems not to have been applied to fuel cell-related membrane materials so far. 

This consideration already shows that hardness is a complex material property because the elastic and plastic properties of the material play a role. In materials that are not linear-elastic and can deform with large elastic deformations, there is no simple relation between hardness and the yield strength. This is illustrated by rubber, which cannot be indented permanently, resulting in an infinite hardness. 

The understanding of further steps in the structure formation process, specifically, forming a network of water-filled pores or ionic domains, is bound to much greater uncertainty. A look at debates in the literature and at conferences leaves no doubt about this. This chapter strives to explain how the interplay of elastic and electrostatic properties of bundles determines the total uptake and the distribution of water in the porous network. This interplay holds the key toward unraveling the relation between micro- and macroscopic swelling and toward rationalizing transport properties of PEMs. 

In the literature, many empirical relationships have been used to relate elastic and mechanical properties to porosity of brittle solids. However, these relationships are generally valid for a restricted range of porosity and their exponent is empirical and depends on the nature of the solid phase. 

One of widely used methods in research elastic and relaxation properties of polymers in the block at periodic sinusoidal loadings is the method of Aleksandrova-Lazurkina [6]. Unlike resonant this method is applied for high elasticity deformations of polymers in the field of the frequencies lying considerably below own frequency of the sample - far from resonant area. In this case, the phase relations, phase lag of deformation fi om stress-relaxation time is determined only by or through the appropriate... 

The -R2(Mo04)3 compositions have been and probably will continue to be a rich source of interesting phenomena related to coupled electrical, elastic and optical properties, which are fortutiously available at room temperature or above in high quality crystals readily grown. 

Some diseases, such as diabetes mellitus and sickle cell anemia, change the mechanical properties of RBCs a reduction of RBC deformability was found to be responsible for an enhanced flow resistance of blood [221]. Therefore, it is very important to understand the relation of RBC elasticity and flow properties in capillaries. The flow velocity at the discocyte-to-prolate transition of fluid vesicles and at the discocyte-to-parachute transition is shown in Fig. 33 as a function of the bending rigidity and the shear modulus, respectively. In both cases, an approximately linear dependence is obtained [187],... 

These adhesive interactions are related to elastic deforma-tion. A number of models have been developed to describe the elastic and relocation properties of cross-linked polymer networks (see Table 3). 

The second area of modeling research relates to the constitutive modeling of the rheological behavors (e.g. viscosity and elasticity) and thermal properties (e.g. density, specific heat, and thermal conductivity) of polymeric materials to better simulate the experimental observations. For example, a checkerboard structure of the... 

---